I'm trying to count a certain number of pulses using an op-amp connected to the sound module.In addition, I'm interested on counting these pulses on certain amount of duration.The LED will turn on if this certain amount of pulses occurs on this duration.

This code counted the number of pulses and when reaching a 14 pulse LED turns on for a while and then start counting again.

The problem I'm facing now is how to count the pulses in certain amount of time. For example , count the number of pulses in 10 seconds only. If the number of pulses reaches 14 in these 10 seconds turn the LED on and start time and count again.

I tried some different loops like for, while but nothing works. I also tried to understand the timers but it was complicated specially that I'm still a beginner in Arduinos and my time is limited.

It can do what you need. You just need to re-think how to use it. Look at how other people use the function. You don't need it to count 10 seconds, you need it to be able to tell when 10 seconds has passed.